Unit 6: Statistics

STUDY

PLAY

Box and Whisker Plot

A diagram that summarizes data using the median, the upper and lowers quartiles, and the extreme values (minimum and maximum). Box and whisker plots are also known as box plots. It is constructed from the five-number summary of the data: Minimum, Q1 (lower quartile), Q2 (median), Q3 (upper quartile), Maximum.

Distribution

The arrangement of values that show the spread of the data.

Dot Plot

A statistical chart consisting of data points on a number line, typically using circles.

Frequency

The number of times an item, number, or event occurs in a set of data

Grouped Frequency Table

The organization of raw data in table form with classes and frequencies

Histogram

A way of displaying numeric data using horizontal or vertical bars so that the height or length of the bars indicates frequency

Inter Quartile Range (IQR)

The difference between the first and third quartiles. (Note that the first quartile and third quartiles are sometimes called upper and lower quartiles.)

Maximum value

The largest value in a set of data.

Mean

The "average" or "fair share" value for the data. The mean is also the balance point of the corresponding data distribution.

Measures of Center

The mean and the median are both ways to measure the center for a set of data. • Measures of Spread- The range and the interquartile range are both common ways to measure the spread for a set of data.

Median

The value for which half the numbers are larger and half are smaller. If there are two middle numbers, the median is the arithmetic mean of the two middle numbers. Note: The median is a good choice to represent the center of a distribution when the distribution is skewed or outliers are present.

Minimum value

The smallest value in a set of data.

Mode

The number that occurs the most often in a list. There can be more than one mode, or no mode.

Numerical Data

Consists of numbers only. Numerical data can be any rational numbers.

Outlier

An outlier is an observation that is numerically distant from the rest of the data.

Range

A measure of spread for a set of data. To find the range, subtract the smallest value from the largest value in a set of data.

Skewed Data

When a set of data is not symmetrical it can skewed, meaning it tends to have a long tail on the left or right side.

Statistical Questions

A statistical question is one for which you don't expect to get a single answer. Instead, you expect to get a variety of different answers, and you are interested in the distribution and tendency of those answers. For example, "How tall are you?" is not a statistical question, however "How tall are the students in your school?" is a statistical question.

Variability

Describes how spread out or closely clustered a set of data is. Variability includes range and interquartile range